My gf had a kid with another guy way before I met her, but he’s back in her life now

A little background:<br>My gf and I (both 26) have been dating for 2+ years, and apparently, she had another guy (29) in her life while she was 18 or 19 (she was 19 when she gave birth), and she claims they didn’t have a relationship back then, he was just a random person she met and made-out with, resulting in her getting pregnant. In any case, the kid (6 now) is a boy and he has no memory of the guy. So I have witnessed him growing up and that kid is an absolute sweetheart. I got close with him and I know all about him. She claims the guy that impregnated her didn’t know she was pregnant, she never told him about it. She had a panic attack when she found out she was pregnant and she did say she was ashamed about it, so she kept it to herself, and apparently, he never tried to contact her during that period, though she did know he was the father of her son. I was unaware of this guy and she didn’t tell me until after we went out for a few months. I have to say it wasn’t easy to digest that, and it took me a while to come to terms with it, but I did tell her I wouldn’t be mad at her about it. She was voluntarily transparent about the whole thing after that.<br><br>Recently, this guy somehow found out she had a kid, and he’s back in her life, claiming he wants to be a part of his son’s life. He wants to meet his son, he wants to meet me, and I guess he wants to be a part of her life again, as I did notice they talk a lot lately.<br><br>It’s not easy for me to admit this but I have to be honest here. I did feel jealousy seeing them talking. She says nothing romantic ever happened between them after she found out she was pregnant, but that was a lame excuse for me, and she can’t claim it was a lack of communication because she was just doing her best to translate her feelings from Arabic to English. She was trying to manage a couple of things at once so I understood that, but it was sad to hear her tell me she was frustrated and sad about the whole situation.<br><br>She is now getting really attached to him. I can tell by the way she talks to him, she laughs a lot more when he says something, she’s overall a lot more excited about the things he does or says, and they share memories or experiences I have no idea about.<br><br>I don’t wanna pull her back to me and separate her from her past, I don’t wanna be the partner who is jealous and prevents her from enjoying her life. I don’t wanna ruin her life. I don’t wanna make her doubt her decision to be with me. I don’t want her to regret being open with me. But I don’t wanna lose her either. I love her so much, she’s my first love, and I want to spend my whole life with her.<br><br>What do I do? I really don’t know.